Water Pump Bypass anomaly

AeroE · Post by **AeroE** » Tue Jul 19, 2011 4:47 pm

I have an M38 engine from a barn (1951) find that was rebuilt by the Army in 1957 and has its brass arsenal rebuild tag. It is the older, non reinforced block. Curious to me is that the water pump bypass hose is a ‘U’ shaped steel pipe, running crosswise, rather than the normal ‘L’ shaped rubber hose. Any idea of the why this is?

Boze · Post by **Boze** » Sat Jul 23, 2011 2:32 pm

I'm not sure what you mean by "crosswise" but it was probably put in because it was available and could be made to work or it was just a plain, dumb mistake. Maybe a previous owner thought it would be an improvement.

Post by **wesk** » Sat Jul 23, 2011 3:27 pm

There is some evidence the very early L134's in the M38's had a steel tube instead of a 90 degree hose for the water pump bypass. It used inverted flare fittings. I've seen them on two very early MCxxxxxxx engines. Only the rubber hose is listed in both the Nov 51 ORD 9 and the SEP 55 ORD 9.

AeroE · Post by **AeroE** » Sun Jul 24, 2011 6:14 am

By ‘crosswise’ I meant that the ‘U’ looped to the right side, not fore/aft like the rubber hose. It isn’t an owner modification-it looks factory. Yes the connections are flare fittings. I’ll post a few pictures including the rebuild plate & S/N when my work load slows.

I have two of these barn finds from the same farmer. He used and abused them but did not do many modifications. One has the original paint with hood numbers clearly visible. I’m in the process of breaking them down for evaluation.